Chile earthquake of 1960

Chile earthquake of 1960, the largest earthquake recorded in the 20th century. Originating off the coast of southern Chile on May 22, 1960, the temblor caused substantial damage and loss of life both in that country and—as a result of the tsunamis that it generated—in distant Pacific coastal areas.

Top Questions

How much damage was caused by the Chile earthquake of 1960?

The cities of Puerto Montt and Valdivia experienced extensive damage. Several coastal towns were inundated by a 25-metre (80-foot) tsunami. The combined effects of the disaster left two million people homeless. Though the death toll in Chile was never fully resolved, early estimates of deaths worldwide, ranging into the thousands, were scaled back to 1,655. About 3,000 people were injured. The tsunami traveled across the Pacific Ocean in the hours after the earthquake; the waves killed 61 people in Hawaii, nearly 140 in Japan, and 32 in the Philippines.

How was the tsunami generated?

At the bottom of the Eastern Pacific Ocean, the Nazca plate is being forced under the South American plate. On May 22, 1960, the stress built up by years of increasing compressional force between the rocks of one plate and another was released by fracturing rocks. The force of the sudden movement along a roughly 560–620-mile (900–1,000-km) stretch of the Nazca plate pushed part of the leading edge of the South American plate upward. The shock of this upward thrust also pushed the water above the plate boundary upward, creating a wave that moved outward in all directions.

How does the Chile earthquake of 1960 compare with other recent earthquakes?

With a magnitude of 9.5, the earthquake was the most powerful such event of the 20th century. Other recent earthquakes have caused more damage and loss of life, however. The Indian Ocean tsunami of 2004 was caused by a magnitude 9.1 earthquake; it killed at least 225,000 people in a dozen countries. The Japan earthquake of 2011 had a magnitude of 9.0; it spawned a tsunami that killed an estimated 19,300 people in Japan and knocked out the electrical power to Japan’s Fukushima Daiichi nuclear power plant, creating the world’s second most serious nuclear emergency.

The earthquake hit at 3:11 pm approximately 100 miles (160 km) off the coast of Chile, parallel to the city of Valdivia. The shock is generally agreed to have had a magnitude of 9.5, though some studies alternately proposed that it may have been 9.4 or 9.6. A series of foreshocks the previous day had warned of the incipient disaster; one, of magnitude 7.9, caused major destruction in Concepción. The fault-displacement source of the earthquake extended over an estimated 560–620 mile (900–1,000 km) stretch of the Nazca Plate, which subducted under the South American Plate. As the quake occurred just prior to a revolution in seismologic technology in the 1960s, these figures are based mainly on post hoc analysis.

Chile earthquake of 1960Map depicting the epicentre of the earthquake off the coast of Chile, May 22, 1960.Encyclopædia Britannica, Inc.

Newsreel describing the Chile earthquake of 1960.Universal Studios

Many Chilean cities, including Puerto Montt, where noticeable subsidence occurred, and Valdivia, where nearly half of the buildings were rendered uninhabitable, sustained significant damage. Though the havoc wreaked by the shaking was not inconsequential, most of the casualties resulted from the descent 15 minutes later of a tsunami that rose up to 80 feet (25 metres) high on the expanse of Chilean coastline—bounded by the cities of Lebu and Puerto Aisen—that paralleled the subducting plate. The combined effects of the disaster left two million people homeless. Though the death toll was never fully resolved, early estimates ranging into the thousands were scaled back to 1,655. About 3,000 people were injured.

Chile earthquake of 1960: tsunamiMap showing the extent of the tsunami generated by the Chile earthquake of 1960.Encyclopædia Britannica, Inc.

The enormity of the seafloor shifts that caused the tsunamis was such that the waves that arrived nearly 15 hours later in the Hawaiian Islands—6,200 miles (10,000 km) away—still crested at nearly 35 feet (11 metres) at landfall in some places. The waves caused millions of dollars of damage at Hilo Bay on the main island of Hawaii, where they also killed 61 people. When they reached the main Japanese island of Honshu 22 hours after their generation, the waves had subsided to about 18 feet (5.5 metres) and laid waste to over 1,600 homes and killed 138 people. In the Philippines, tsunami waves left 32 dead or missing. Though the oblique angle by which the waves approached the Pacific coast of the United Statesmitigated their force, Crescent City, California, saw waves of up to 5.6 feet (1.7 metres), and boats and docks in Los Angeles, San Diego, and Long Beach were damaged.

Hilo, Hawaii; tsunami; Chile earthquake of 1960Debris from buildings damaged by a nearly 35-foot (11-metre) tsunami, Hilo, Hawaii island, Hawaii. The force of the wave—caused by an earthquake on May 22, 1960, off the coast of Chile—was enough to bend parking meters to the ground.Sunset Newspaper/National Geophysical Data Center/NOAA